Known latent heat storage means suffer from the drawback that their capacity diminishes with the number of charging cycles and is finally lost completely, since the seed crystals stratify. Therefore, constructions have been devised in which crystallisation takes place on the surface of rotary tube heat conveyors so that a constant recirculation of the molten mixture is assured and stratification of the seed crystals is obviated.
Furthermore, latent heat storage means have become known wherein stratification is prevented by motor driven agitators. The incorporation of motor driven recirculating devices into the storage means construction results in a constant consumption of driving energy.